Gyro vehicle



March 19, 1968 T. o. SUMMERS GYRO VEHI CLE 9 Sheets-Sheet l Filed Apri]19, 1966 INVENTOR.

BY /Rf/ 790/1446 C). Jam/796,

March v19, 1968 T. o. SUMMERS GYRO VEHI CLE 9 sheets-sheet sl F'iledApril 19, 1966 5,. y mm f MN N Ww W JW. m w fw w fk March 19, 1968 T. o.SUMMERS 3,373,832

GYRO VEHI CLE Filed April 19, 1966 9 Sheets-Sheet 4 790/1446 O JUA/Maas,INVENTOR.

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AUTOR/Vg Y Y March 19, 1968 T. o. SUMMERS 3,373,832

GYRO VEHICLE 9 Sheets-Sheet 5 Filed April 19, 1966 March 19, 1968 T. o.sUMMERs GYRO VEHI CLE 9 Sheets-Sheet 6 Filed April 19, 1966 INVENTOR.Zion/4J 0. wmf/Q6,

March 19, 1968 T. o. sUMMERs GYRO- VEHICLE 9 Sheets-Sheet 8 790/1446 0.dwf/M596,

Filed April 19, 196e v INVENTOR.

#WWA/y 3,373,832 Patented Mar. 19, 19618 3,373,832 GYRO VEHICLE Thomas0. Summers, Sherman Oaks, Calif. (1536 Fairway Drive, Camarillo, Calif.93010) Filed Apr. 19, 1966, Ser. No. 543,708 42 Claims. (Cl. ISU-30)This invention relates to gyroscopi'cally stabilized vehicles andparticularly to gyroscopically stabilized centertracking automotivevehicles supported on running wheels arranged in tandem to allowsubstantial attitude variations or banking freedom about a roll axispassing through the points of contact of the wheels with the ground.

When a conventional tandem wheeled center-tracking vehicle, such as amotorcycle, is at rest or is moving in a straight line, gravitydetermines the equilibrium position of the center of mass of the ladenvehicle; that is, the vehicle proper, plus its load. In its balanceposition, if the line of action of gravity is represented by a verticalray originating at the center of mass, the vertical ray will intersectthe roll axis. In any other position, a force moment is produced aboutthe roll axis with the magnitude of the moment being in directproportion lto the lateral displacement of the vertical ray from t-heroll axis.

When a conventional two-wheeled vehicle is moving along a curved path,various forces determine the equilibrium position of the laden vehicleabout the roll axis. To insure equilibrium the roll moments produced bygravity, lateral acceleration (centrifugal inertia force) and otherforces must add vectorially t-o zero, p Disregarding these other forces,a laden vehicle, under the influence of gravity and centrifugal force,is in equilibrium only if a ray originating at its center of mass andrepresenting the line of action of the resulta-nt of gravity andcentrifugal force, passes through the roll axis. In this situation, thelateral tilt of this ray from the vertical, that is, the bank angle ofthe laden vehicle, is equal to the angle a plumbline is displaced fromvertic-al under the identical influence of gravity and centrifugalforce.

Inuences in addition to gravity and centrifugal force may alter theladen vehicles equilibrium bank angle relative to the plumbline angle orapparent vertical. In a high speed turn, for example, the gyroscopiceffect of the running wheels produces a gyro moment about the roll axisin the same direction as the moment produced by centrifugal force. In aconventional two-wheeled vehicle, this gyro moment can be equilibratedby allowing the laden vehicles bank angle to exceed the plumbline angleby the amount necessary to establish roll equilibrium. This overbank, orincrease in the bank angle, correspondingly increases the roll momentproduced by gravity acting on the mass particles of the laden vehicle,which moment is opposite in direction to the gyro moment.

Unlike this gravity roll moment which is determined by the ladenvehicles bank angle, the roll moment produced by centrifugal force isdetermined by the displacement of the vehicles steered front wheel andhandlebars. T-he cyclist steers the front wheel in one direction to rollhis vehicle in the other.

A conventional two-wheeled vehicle such as a motorcycle may be guided bycontrolling its bank angle with roll moments effected by such steeringor handlebar displacement. To turn left, the handlebars or roll controlmeans are turned first to the right. The resulting centrifugal forcemoment effects a left roll. As the vehicle rolls left toward a bankangle appropriate to the desired left t-urn path, the handlebars andfront wheel are turned back and to the left of their normal or centerposition, to reverse the centrifugal force moment and stop the roll. Toeffect a coordinated right turn, the procedure is reversed.

Another method of banking into a turn is for the cyclist to shift hisown weight laterally relative to the plane of symmetry of the vehicleproper. This shifts laterally t-he center of mass of the laden vehicle.In this situation the bank angle of .the laden vehicle will be greaterthan the bank angle of the plane of symmetry of the vehicle proper andthe gravity moment will be in the direction the cyclist leans or shifts-his weight. To turn left, the cyclist leans left. This starts a leftroll which the cyclist stops with centrifugal force by turning thehandlebars or roll controller to the left. To turn right t-he procedureis reversed. The eifectivity of the body lean method of controllingroll, however, is limited to the extent to which the cyclist can shifthis body laterally.

Caster shifts laterally, according to front wheel displacement, thecenter of mass of the laden vehicle relative to the roll axis. Massshift effected by conventional or positive front Wheel caster is towardthe inside of the turn and augments mass shift effected by roll and/orbody lean, so that less lateral tilt of the vehicles plane of symmetryis required to effect a given bank angle of the laden vehicle.

In a coordinated turn, the roll moment due to positive caster isopposite in direction to the roll moment due to centrifugal force, andfor a given front wheel displacement the combination of these momentstend to roll the vehicle in one direction at zero and near zero speeds,and in the opposite direction at high speeds. Below the crossover speedthe gravity moment due to positive caster exceeds the centrifugal forcemoment due to front wheel displacement, and the cyclist may find itnecessary to augment the centrifugal force moment by shifting his ownweight toward the outside of the turn.

Indeed, in certain high speed, narrow, enclosed motorcycles, in whichthe cyclist cannot lean his body appreciably, retractable Outrigger sidesupports are used to hold the vehicle upright below the crossover speed.This crossover, or minimum control speed is a function of positive frontwheel caster.

Although such caster raises the minimum speed at which equilibrium canbe maintained by ordinary methods, it is nevertheless considereddesirable in conventional two-wheeled vehicles because it effects afront wheel torque tending to center the roll controller. This centeringtorque is relied on to assist the cyclist in controlling a conventionaltwo-wheeler.

The gyro stabilized vehicle of the present invention employs front wheelcaster, but it is a negative caster. Negative caster, unlike positivecaster, facilitates stabilization at zero and near zero speeds, makingit unnecessary for the vehicle of the present invention to be in motionto maintain equilibrium. The gyro vehicles steered front wheel ispositioned by a steering motor or servo which renders the rollcontroller immoble to caster torque so that steering wheel centeringtorque due to caster is without effect on the vehicle.

The basic stabilizing apparatus of the vehicle according to the presentinvention employs a large gyro rotor supported in a frame on bearingsallowing high speed rotor spin. The gyro gimbal 0r frame, in turn, ispivotally supported about an axis preferably at right angles to the spinaxis, on anti-friction bearings xed to the chassis of the vehicle sothat the pivot axis of the gyro frame is preferably at right angles tothe roll axis of the vehicle. The arrangement is such that the gyro andthe vehicle have a common roll axis, for example, a line through thepoints of contact of the running wheels of the vehicle with the supportsurface, so that neither the gyro nor the vehicle can roll independentlyof the other.

The pivot axis of the gimbal may be located in any positionperpendicular to the roll axis; but its preferred location is parallelto the vehicles centerplane. When the gyro gimbal axis is fixed in thisideal location, turns can be made with equal facility in eitherdirection and only when it is fixed in this location. Also, in otherlocations, pitching of the vehicle may disturb steering. When the gyrois in its normal and most effective stabilizing position, its spin axisis at right angles to the roll axis. It is understood that when thevarious axes are referred to as being at right angles, or perpendicularto each other, they may in fact be offset or spaced with respect to oneanother so that they do not actually intersect.

So long as the gyro is free to precess about its gimbal axis and ismaintained at or near its normal and most effective stabilizingposition, the vehicle cannot be rolled by force applied about its rollaxis. The gyro responds to such force by precessing about its gimbalaxis, for example, as a function of lateral displacement of the centerof mass of the laden vehicle with respect to apparent vertical. Thisprecession will be in one direction when the vehicles center of mass isdisplaced to the left of apparent vertical and in the other directionwhen the vehicles center of mass is displaced to the right of apparentvertical. In other words, the direction and rate of gyro precessionabout its gimbal axis is determined by the bank angle of the ladenvehicle with respect to apparent vertical. The vehicles bank angle ismanually controlled by torquing the gyro about its gimbal axis, andapparent vertical is automatically controlled by servo positioning ofthe steered front wheel according to the displacement of the gyro fromits normal position; that is, the position at which the spin axis isperpendicular to the roll axis.

In turns, therefore, roll moments produced by lateral accelerationaccording to front wheel displacement, and roll moments produced bygravity as a function of bank angle, must be coordinated in the properopposing relationship to keep the gyro from departing excessively fromits normal position. Time is required to effect such coordination andcontrol of gyro precession and during this time, the gyro will departfrom its normal position. This time lag must be kept low to contain gyrodisplacement within tolerable limits.

In the gyrocar of the present invention, this time lag is minimized bysteering the front Wheel with a high response steering servo. This servopositions the front wheel automatically as a function of gyrodisplacement from its normal position. Roll torque is produced accordingto the lateral acceleration resulting from the gyro controlled frontwheel displacement. To initiate a turn, the weight of the gyrocar isshifted laterally by banking in the direction of the desired turn. Thisproduces a roll moment due to gravity which precesses the gyro. Theresulting gyro displacement is accompanied by a proportionaldisplacement of the steered front wheel. This causes a turn or lateralacceleration of the vehicle, producing a centrifugal force momentproportional to lateral acceleration and in opposition to the gravitymoment. Until the gravity moment is equilibrated, the gyro displacement,front wheel displacement, lateral acceleration and the centrifugalinertia force moment, increase. This decreases the precession rate untilproper coordination or equilibrium is achieved and precession stopsrelative to the vehicle.

In known steerable, gyro stabilized, tandem wheeled vehicles, it hasbeen the common practice to initiate turns by displacing the steerablefront wheel without first banking. The resulting lateral accelerationimposes a roll moment on the vehicle, and an attempt is made to shiftthe weight of the vehicle laterally, by banking or other means, toachieve roll equilibrium before the vehicle upsets. In a severe turnentered suddenly, this effort may be unsuccessful due to the inertia ofthe mass being shifted.

In the gyrocar of the present invention, the steering movement of thefront wheel may be eected directly by the gyro through linkage orgearing providing the gyro with a high mechanical advantage over thesteered wheel.

This mechanical advantage, in effect, renders the gyro insensitive totorques about the steering axis due to road shock and negative caster.

Preferably, however, the work of positioning the steered front wheel isperformed by steering mechanism comprising a gyro controlled servomotor. In either event, gyro precession is followed automatically by arelated steering movement until the corresponding change in lateralacceleration stops gyro precession relative to the vehicle which, inturn, stops the steering movement.

In a turn, if a laden gyrocars center of mass were banked to apparentvertical the gyro would, nevertheless, depart from its normal positionbecause of the inherent tendency of such a gyro to rern'ain fixed inspace. In a turn, therefore, the laden vehicles bank angle is not theplumbing line angle. It varies sufficiently from a plumbline angle toproduce a roll torque and precess the gyro about its gimbal axis at thesame rate that the vehicle is turning. With the gyro oriented in itspreferred location; that is, with its pivot axis fixed in a positionparallel to the centerplane, the laden vehicles bank angle in a turn caneither be greater or less than the plum-bline angle according to thedirection of rotor spin.

In this preferred orientation of the gyro, the spin axis is normallyparallel to the fixed axis of rotation of the rear running wheel. If thegyro rotor is caused to spin in the same direction that this runningwheel rotates when the gyrocar is in forward motion, the laden vehiclesbank angle will be greater than the plumbline angle and the vehicle willoverbank for both right and left turns. On the other hand, if the gyrorotor is caused to spin in the opposite direction, the vehicle willunderbank for turns in either direction.

The direction in which the gyro rotor spins also determines thedirection the front wheel is moved -about its steering axis in relationto gyro precession. In an overbanking gyrocar, when the gyro gimbalprecesses or pivots to the left, the front wheel steers to the left andwhen the gimbal precesses to the right, the front wheel steers to theright. In an underbanking gyrocar, when the gyro pivots to the left orright, the front wheel steers to the right or left, respectively.

Generally speaking, steerable wheeled vehicles tend to oversteer whenthe rear end is heavy and understeer when the front end is heavy. A rearheavy gyrocar which other- Wise might oversteer, can be made to steermore naturally by adapting the vehicle to overbank in turns. Inoversteering vehicles, there is a tendency for the rear end to runoutward more than the front end. This tightens the turn, and requiresthe driver to steer away from the inside of the turn. This steeringreversal or corrective action on the part of the driver must be effectedquickly to restore control should the rear end break outwardly or skid.This corrective action is facilitated in a rear heavy gyrocar if thegyro rotor spins in the direction resulting in overbank.

In a rear heavy, overbanking gyrocar, the proper response to rear endbreakaway is quick and automatic. When the rear end starts to skidoutward the gyro automatically moves the front wheel in the direction tosteer the vehicle away from the inside of the turn, thus saving thedriver from a potentially unstable situation.

In a front heavy understeering vehicle, on the other hand, the front endtends to run wide in a turn. To overcome this tendency, in negotiating acurve the driver must increase the cornering force by excessive inwardsteering. This corrective action is natural for the average driver sinceit merely involves steering more sharply in the direction of theintended curve. Should, however, the heavy front end suddenly `breakaway, or skid outwardly, theproper corrective action would require aquick steering reversal. This action can be provided automatically in afront heavy gyrocar by adapting the vehicle to underbank in a turn, In afront heavy, underbanking gyrocar, when the front end starts to skidoutward, the gyro automatically steers the front wheel outward; that is,in the direction of the skid.

For a given front wheel displacement, lateral acceleration increasesapproximately according to the square of the vehicles speed. At a lowspeed, therefore, a much larger front wheel displacement is necessary toachieve a given lateral acceleration (centrifugal inertia force) than ata high speed. If the ratio of gimbal movement to front wheel movement ishigh, and the vehicle speed is low, the gimbal may run out of travel inorder to effect a required lateral acceleration or front wheeldisplacement. On the other hand, if this ratio is low; at high speed,small amplitude gimbal oscillations such as might be caused by randomtorques due to unbalance and road conditions may result in dangerouslateral accelerations. Therefore, for a gyrocar capable of high speedtravel, lateral acceleration or front wheel displacement is controlledautomatically by gyro gimbal displacement in a ratio preferably changingapproximately as the square of the cars speed, so that for anyparticular gimbal displacement, the turning radius of the vehicle athigh speed is much greater than at low speed.

It is therefore anobject of the present invention to provide novel meansfor imparting stability to an otherwise unstable vehicle.

Another object of the present invention is to provide a gyrocar in whichthe driver effects turns by torquing the gimbal until the car precessesor banks to a roll attitude corresponding to his desired rate of turn.

Another object of the invention is to provide a gyrocar in which thedriver -controlled roll precession disturbs the equilibrium of the carand causes the gyro gimbal to precess and automatically alter thedisplacement of the front Wheel about its steering axis in a directionto restore equilibrium.

Another object of the present invention is to provide a gyrocar in whichthe front wheel has negative caster to move the vehicle sidewaysrelative to its roll axis, when displaced, and produce a gravitationalmovement auginenting any roll moment due to lateral acceleration. Inkeeping with this object, the augmenting gravitational moment is maximumat zero speed and minimum at'top speed, so that vehicle equilibrium ismaintained with more or less equal eifectivity throughout the entirespeed range.

Another object of the present invention is to provide a gyrocar in whichthe simple act of steering the car automatically maintains the gimbal inthe vicinity of the position at which it is most eiective in resistingroll, and in which, when not in motion, the simple act of centering theattitude controller, centers the gimbal to its most eifective position.

Another object of the present invention is to provide a center-trackingwheeled vehicle which turns automatically according to roll attitudescontrolled by the driver, and in which force moments are controlledautomatically to maintain equilibrium in the attitudes the driverestablishes.

Another object of the invention is to provide a gyro Vehicle in whichlateral acceleration or front wheel displacement is controlledautomatically by gyro gimbal displacement in a ratio changingapproximately as the square of the vehicles speed.

These and other objects of the invention not Ispecifically set forthabove will become-readily apparent from the accompanying description anddrawings in which:

FIGURE 1 is a top plan view of the gyro vehicle of the present inventionshowing in dotted lines the location of the various major components ofthe vehicle;

FIGURE 2 is a side elevational view along line 2 2 of FIGURE 1 showingthe rear drive wheel and the front steered wheel;

FIGURE 3 is a partial plan view along line 3 3 of FIGURE 2 of the frontportion of the Vehicle illustrating the steered front wheel and thegyro;

FIGURE 4 is a partial section along line 4 4 of FIG- URE 3 illustratingthe supporting structure for the gyro and for the front wheel;

FIGURE 5 is an enlarged partial plan view similar to FIGURE 3illustrating the linkage for controlling the steering motor inaccordance with gimbal displacement;

FIGURE 6 is a partial vertical section along line 6 6 of FIGUR-E 5showing the valve controlled by gimbal displacement;

FIGURE 7 is a vertical section along line 7 7 of FIGURE 5 showing thegain control in the follow-up linkage connected to the front wheel:

FIGURE 8 is a partial transverse vertical section along line 8 8 ofFIGURE 6 illustrating the Ifollow-up linkage between the front wheel andthe valve connected to the gyro gimbal;

FIGURE 9 is a transverse vertical section along line 9 9 of FIGURE 4showing the steering mechanism for the front wheel and the follow-uplinkage connected therewith;

FIGURE l0 is a vertical section along line 10-10 of FIGURE 9illustrating the gear drive connected with the steering motor;

FIGURE 11 is a transverse vertical section along line 11-11 of FIGURE 4showing the steered front wheel suspension;

FIGURE 12 is a transverse vertical section along line 12-12 of FIGURE 4showing the gyro gimbal supporting the gyro rotor;

FIGURE 13 is a vertical section along line 13 13 of FIGURE 3 showing thevalve controlled by the steering wheel (roll controller) shaft forturning the vehicle;

FIGURE 14 is a transverse vertical section along line 14-14 of FIGURE 13showing the valve spool and follow-up sleeve of the manually controlledvalve;

FIGURE 15 is a transverse vertical section along line 15-15 of FIGURE 13showing a different section of the manually actuated valve;

FIGURE 16 is a transverse vertical section along line 16-16 of FIGURE 13showing the centering spring for the manually actuated valve;

FIGURE 17 is a partial transverse vertical section along line 17 17 ofFIGURE 13 showing the spring for centering the control valve relative tothe frame;

FIGURE 18 is a transverse vertical section along line 18-18 of FIGURE 6showing the valve actuated by the gyro gimbal for controlling movementof the steered front wheel;

FIGURE 19 is a horizontal section along line 19 19 of FIGURE 18 showingthe valve elements;

FIGURE 20 is a diagrammatic illustration of the stabilization system forthe vehicle steered by the roll controller (steering wheel);

FIGURE 21 is a diagrammatic illustration similar to FIGUR-E 2O in whichthe Vehicle has been placed in a left turn;

FIGUR-E 22 is a diagrammatic illustration of the top of the vehicle asshown in FIGURE 20 showing the direction of mass shift due to negativecaster;

FIGURE 23 is a schematic illustration of the hydraulic system utilizedfor the stabilized vehicle and showing side supports for holding thevehicle upright when not in use;

FIGURE 24 is a diagrammatic illustration of a second form of theinvention in which the gyro rotor spins in the same direction asmovement of the running wheels of the vehicle during forward movement;

FIGURE 25 is a diagrammatic illustration of a third yform of theinvention showing the manually operated roll controller (steering wheel)for manually torquing the gimbal;

FIGURE 26 is a diagrammatic illustration of a fourth form of theinvention in which the gimbal is mechanically torqued by the steeringwheel and the gimbal mechanically steers the front wheel; v

FIGURE 27 is a diagrammatic illustration of a fifth form of theinvention in which the gimbal axis is substantially perpendicular to thelongitudinal centerplane of the vehicle; and

FIGURE 28 is a diagrammatic illustration of the vehicle of FIGURE 27 ina left turn.

First embodiment Referring to the first embodiment of the inventionillustrated generally in FIGURES l and 2, the gyro stabilized vehicle 30has a body 31 which contains seats 32 and 33 for two passengers sittingside by side with the drive-r seated behind the roll controller orsteering wheel 34. The vehicle Ican have any suitable type of fir-amewhich serves to support .an engine 35 and the gyro assembly 36. Theengine drives a pump 29 which supplies hydraulic fluid under pressure tothe stabilizing components of the vehicle. The engine also drives thetransmission 37 which is connected `to one end of driveshaft 38 byuniversal joint 39. The opposite end of the ydriveshaft 38 connects withuniversal 40 which in turn connects with shaft `41 leading to the rearwheel 42. The rear Wheel 42 and shaft 41 are supported by `a framelmember 43, and a gear 44 on the end of shaft 41 meshes with gear 45 onthe wheel. The member 43 is rigidly connected to a tube 48 which isrotatably supported in brackets 49 and 50 secured to the frame o=f thecar. Thus, rear wheel 42 can move up and down relative to the car frameabout the axis of the tube 48 and the universal joint 40 permits thegear 44 to impart a `driving force to the wheel regardless of itsposition relative to the frame. A stick shift lever y54 controls thetransmission to control the `speed of the car, and a suitable springsupport (not shown) may be employed to suspend the rear wheel.

The steered front wheel 55 of -the vehicle is free-running and ismounted n a double caster arm 56; the outer ends 57 of the arm beingformed into the support shaft for the front wheel. The other ends 58 ofthe caster arm are rigidly secured to ends 59a and `60a of spaced bars59 and 60 which are :supported at ends 5912 and 60b by enlargements 61and 62, respectively, on a mounting shaft `63 (see FIGURES 9 and l0). Adriving pin 65 exten-ds through ends 59h, 6011 and through enlargementprojections 61 and 62 and through the mounting shaft 63. The lower endof pin 65 carries a pulley 66 and the upper end of pin 65 contains asquare socket 66' for receiving a square drive pin 67. The lower end ofpin 65 is splined at 68 so that rotation of the pin 6'5 by drive pin 67will lcause Ithe bars 59 and 60 to rotate thereby turning caster arm 56and lfront wheel '55. Referring to FIGURES and 8, the vehicle framecomprises frame arms 70 and 71 having enlarged ends 70a and 71a,respectively, which receive the reduced ends 63a an-d 63h of shaft 63.The ends 70a and 71a contain .suitable bearings for rotatably supportingthe ends of the shaft 63 so that lthe caster arm 56 and the front wheelcan move up and down relative to the car frame.

The drive pin `67 is rotatably driven by steering unit 75 whichcomprises a casing 76 rigidly secured to the shaft 63 by means ofbrackets 77 and 78 (see FIGURES 9 and A hydraulic steering motor 80 isattached -to casing 76 and has a drive shaft 81 (see FIGURE 5)terminating in a worm gear `82 which meshes with gear 83. The gear 83 isrotatably supported by the casing and has a shaft 84 connecting with asprocket 85 around which passes a chain 86. The chain also passes arounda larger sprocket 87 from which projects the driven pin 67. Thus,rotation of worm gear ,82 by motor 80 will rotate gear 83 and drivechain 86 to cause pin `67 to move the Ibars 59 and 60 and the caster arm56. Since the steered -front wheel is forward of its pivot pin 67, thefront wheel caster is negative. While a hydraulic gear motor of standardconstruction is utilized to steer the front wheel, any other suitabletype of :steering motor,

such as an electrical or mechanical motor or actuator can be employedfor this purpose.

In order to .spring mount the front wheels, the frame members 70 and 71carry lugs 90 and 91 which engage one end of coil springs 92 and 93,respectively, (see FIG- URES 3 and 5). The other end of spring 92 restsin a seat 95 secured by a bracket 96 to splined end 97 projecting fromend 63a of shaft 63 and end nut 98 holds the bracket 96 on the splinedend 97. In a similar manner, spring 93 rests in a seat 100 secured by yabracket 101 to splined end 102 projecting from end 63b of shaft 63 andthe bracket is held on the splined end 102 by a nut 103 (see FIGURE 8).Thus, the brackets 96 and 101 will move with the wheel 55 as it moves upand down and the springs will serve to continually bias the wheel 55 ina downward direction. Suitable shock absorbers (not shown) can beincorporated in the springs in a conventional manner.

A gyro stabilizing unit 105 of assembly 36 comprises cylindrical gyroframe 106 which is rigidly secured to vehicle frame tube 108 by weldingat location 107. In addition, a U-shaped frame support member 109 isconnected to opposite sides of the gyro frame 196 and this member issupported by a bracket 110 (see FIGURE 3) which is welded to ahorizontal frame member t111 extending from the rewall 112 to connectwith the top of the frame 106. Obviously, additional frame members canbe incorporated `to provide the required mounting rigidity for the gyroframe.

Referring to FIGURE 12, the rigid gyro frame 106 rotatably supports agyno gimbal 115 having upper and lower shafts 116 and 1117 which carrybea-ring structures `118 and 1l19, respectively. The gyro frame hasupper and lower stub shafts 120 and 121 iixed thereto by screws 122 andIthe ends 120a and 121:1 project into the bearing structures 118 and119, respectively. The stub shaft 120 contains a passage 125 and asimilar passage 126 is contained in stub shaft 12.1. Passage 125connects with passage 127 in shaft 1l16, and passage 126 connects withpassage 130 in shaft 117. Therefore, hydraulic fluid supplied to passage125 Ithrough conduit 131 can flow, ,through the axis of the bearing 118,to a passage 128 which connects with hydraulic motor 133 mounted inprojection l135 on the gimbal 115. The shaft 141 of motor 4133 passesthrough an opening in gimbal 115 containing bearing 142 and is keyed toshaft 143 of gyro rotor 139 by means of key 144. Rotor shafts 138 and143 are attached to a solid central web 145 ywhich supports the gyroring 146 comprising the major mass of the gyro rotor 139. Shaft 138 isrevolvably mounted in bearing 137 supported by the gimbal. Acounter-weight 132 is attached to the gimbal projection y134 opposite tothe motor 133 to balance the gimbal, it being understood that thecounter-weight 132 may be replaced by another hydraulic motor similar tomotor 133. The motor 133 exhausts ithrough passages 151, 126 and 152.

Referring to FIGURES 4 and 5, the gyro gimbal 115 has a bottom blockprojecting therefrom and an actuator arm 156 is pivotally attached toone side of the block while an actuator arm 157 is pivotally attached tothe opposite side of the block. The actuator arm 156 is moved by a lowfriction piston type actuator motor 158 which is pivotally connected bypin 159 to the frame 160 for the engine 35 (see FIGURE 3). In a similarmanner, the actuator arm 157 is driven by low friction piston typeactuator motor 161 which is pivotally connected by pin 162 to the engineframe 160. Fluid is supplied to the motors 158 and 161 through passages164 and 165, respectively -(see FIGURE 5 Under normal operatingconditions, substantial fluid pressure is not applied to the actuators158 and 161 and because of the low friction construction of theseactuators, normally they will not interfere appreciably with themovement of the gimbal. However, when it is desired to torque the gyrogimbal in order to bank the vehicle, as will be later described,pressure can be applied to either one of the actuators to torque thegimbal in the desired direction about the gimbal axis. The torquingmotors can comprise any suitable actuator or motor, either electrical,hydraulic or mechanical.

The supply of fiuid under pressure to the torquing motors 158 and 161 iscontrolled by valve 170 (see FIGURES 13-17). Valve 170 has an inputshaft 171 which connects with steering shaft 172 of steering wheel (rollcontroller) 34 and the shaft is supported by a conventional steeringcolumn 172 (see FIGURE 2). The input shaft 171 is normally centered inthe valve casing 173 by a centering spring 178 having ends 178:1 and178b on opposite sides of a housing projection 173a and of a pin 173b(see FIGURES 13 and 17). A collar 179 is fixed to shaft 171 by a pin179a and pin 173b projects into collar 179 so that spring 178 centersthe input shaft 171 when no steering force is applied thereto. A disc179b is turned with collar 179 by pin 173b and the disc 179b contains Ianotch 179e for projection 173a so as to limit the angular movement ofthe input shaft in both directions relative to the valve casing 173.

Valve casing 173 contains a follow-up sleeve 174 which is connected atend 174:1l to a pulley 175 by a key 176 and the pulley is held on end174a by ring 177. The casing 173 also contains four ports 180-183 withports 180 and 182 arranged in one transverse plane and ports 181 and 183in a second transverse plane spaced from the first plane (see FIGURE14). Fluid under pressure enters the port 180 and exhausts through theport 1182. Port 181 connects with rtorquing motor 158 through line 164and port 183 connects with torquing motor 161 through line 165. Thefollow-up sleeve 174 has a first semi-circular manifold groove 190 and asecond semi-circular manifold groove 191 (see FIGURE 13). These twogrooves are separated by projections 192 and 193 extending outwardly tothe casing 173 so that grooves 190 and 191 are separated from oneanother (see FIGURE 14). The fluid from passage 180 is introduced togroove 190 and then flows through opening 194 in sleeve 174 into thespace 195 within the follow-up sleeve 174. Space 195 is separated fromspace 196 within the sleeve by a valve spool 200, which comprises atriangular wedge 201 terminating in end surfaces 202 and 203. Space 196is connected to exhaust passage 182 through opening 197.

A second set of semi-circular manifold grooves 206 and 207 in sleeve 174are spaced from the manifold grooves 190 and 191 by the seal 20711 andthe grooves 206 and 207 are separated from one another by extension 208and 209. As illustrated in FIGURES 14 and 15, the grooves 206 and 207are displaced 90 degrees from the grooves 190 and 191. End rings 204 and205 on the valve spool 200 are located at the opposite ends of the wedge201 and span the two sets of manifold grooves. The sleeve 174 contains afirst set of three openings 210, 211 and 212 which open into manifoldgroove 206 and contains a second set of three openings 213, 214 and 215which open into manifold groove 207. As illustrated in FIGURE 15, themanifold groove 206 connects with passage 165 and the manifold groove207 connects with passage 164.

In operation, when the valve spool 200 is in the null or center positionas illustrated in FIGURE 14, liuid fiows from passage 180 into space 195and then out the openings 210 and 213 into the annular manifolds 206 and207 so that fluid is supplied equally to passages 164 and 165. At thesame time, the ports 212 and 215 are open to connect the fluid to space196 which in turn exhausts through the port 182. Thus no appreciablepressure will build up on the actuators 158 and 161 with the valve spoolin its center position.

When it is desired -to operate one actuator or the other, the valvespool 200 is rotated in the required direction. For instance, whenrotated to the dashed line position of FIGURE 15, ports 212 and 213 areclosed and fluid flows through ports 210 and 211 into manifold 206 andthen to torquing actuator 161 through line 165. At the same time,passage 164 will remain open to space 196 through openings 214 and 215so that torquing actuator 158 is connected to exhaust port 182 throughopening 197. In the event the valve spool 200 is rotated in the oppositedirection, line 164 would be supplied with uid under pressure toenergize torquing actuator 158 and line 165 would be connected toexhaust through port 182 so that the gimbal will be torqued in theopposite direction. Thus, when the valve spool 200 is in the centerposition, the fluid ow will be from the input port 180 to the outputport' 182 with no substantial pressure produced by the actuators 158 and161 and the gimba'l can rotate freely in the frame 106. However, whenthe spool 200 is rotated, a torquing force will be produced on thegirnbal in a direction determined by the direction of rotation of thespool.

The spool 200 has an end extension 222 supported by bearing 223 withinsleeve 174 and the extension is connected to steering shaft 171 by ashaft 224. The end of extension 222 is connected to shaft 224 by meansof a floating coupling 225 which has a grooved end 226 fitted to theshaft 222 .by lug 227 and has a cup end 228 fitting over the end ofshaft 224 (see FIGURE 13). The coupling 225 has a lug 229 which islocated in a groove 230 in shaft 224 and shaft 224 is rotatably mountedby needle bearing 231 on supporting cup end 228. Thus, the coupling 225permits some misalignment between the shafts 222 and 224 to minimizebinding of the spool 200.

The shaft 224 is surrounded by a coil spring 235 which has opposite ends236 and 237 located in a groove 238 in follow-up sleeve 174 (see FIGURES13 'and 16). A rod 239 extends longitudinally through the groove 238land into openings in the sleeve 174 at opposite ends of the groove 238so that the rod 239 is rigid with the sleeve. A second rod 240 extendsbetween openings in hub 241 and in cup end 228 and is normally locateddirectly above the rod 239 by the ends 236 and 237 of spring 235 whichare located on opposite sides of rods 239 and 240. The spring 235 servesto normally maintain the spool 200 centered within the follow-up sleeve174 as illustrated in FIGURES 14 and 15. Shaft 224 extends into anopening in the end of steering shaft 171 and is secured thereto by pin179a and a bearing 243 supports the end of the shaft 224. The bearing243 is secured by a ring 244 which in turn is secured by snap ring 245held by casing 173.

When the steering shaft 171 is rotated, it will turn the spool valve 200relative to the follow-up sleeve 174 since the rod 240 will rotate withthe shaft 171 and spread the ends of the spring 235 apart. The rod 239will remain stationary with the follow-up sleeve during this initialmovement. When -an end of the spring 235 engages a side of groove 238,no further displacement of the spool relative to the sleeve can takeplace. Therefore, there is a limit to the maximum relative rotationbetween the spool and the sleeve and once the force on the steeringwheel is removed, the spring 235 will center the valve by moving thespool and steering wheel back tothe open center position. It istherefore apparent that movement of the steering wheel or rollcontroller 34 will move the valve spool 200 which in turn will controlthe actuators 158 and 161 to produce a torque on the gyro gimbal in theselected direction. As will be later described, the application of atorquing force on the gyro gimbal will cause the vehicle to bank aboutits roll axis resulting in a turn in the direction of the bank.

In order to turn the steered front wheel of the vehicle as a function ofgimbal precession, a link 250 is pivoted to the gimbal 115 by a pin 251extending from the gimbal into the enlarged end 250a of the link (seeFIGURES 5 and l2). The other enlarged end 250b of link 250 receives apin 252 which is carried by blade 253 extending from a split member 254attached to shaft 255 of the valve 256 (see FIGURE 18). The valve 256 isidentical in construction with the valve 170 except that centeringsprings, such as springs 235 and 178 are not employed. Shaft 255 turnsthe spool 200 which directs the iluid received from passage 180 to theports 210', 211', and 212 or to the ports 213', 214 and 215 in order tocontrol the flow of uid to the output passages 257 and 258 and to theoutput exhaust passage 182. The followup sleeve 17e projects beyond theend of the valve casing 173 and carries a follow-up member 259 which iskeyed to the follow-up sleeve by key 259. The spool 200 is supportedwithin the follow-up sleeve by the bearings 221 and 223. Passages 257and 258 co-nnect with the hydraulic motor 80 which drives the steeringymechanism 75 for the front wheel 55. When the lgyro gimbal precesses inone direction, the motor is driven in a direction to turn the vehicle inone direction and when the gyro gimbal precesses in the other direction,the motor 80 is driven in the reverse direction to turn the vehicle inthe opposite direction.

With the rotor 139 spinning in the preferred direction (the directionindicated in FIGURE 20) upon banking the vehicle to the right, gravitywill precess the gimbal counterclockwise and move the arm 250 to theright in FIGURE 5 and the valve spool 200 in a direction t0 introduceduid to line 257 which will rotate motor 80 in a direction to steer thefront wheel 55 to the right. Upon banking the vehicle to the left,gimbal precession will move the link 250 and valve 256 will introducefluid to passage 258 to drive the motor 8) in a direction to steer thefront wheel to the left. Thus, it is apparent that the front wheel 55will be steered by gyro precession in the direction of vehicle bank.

In order to turn the front wheel as a function of gimbal displacement, afollow-up cord 260 is rotated by the pulley wheel 66 which is rotated bythe steering motor when the front wheel is rotated about its steeringaxis (see FIG- URE l). One end of the cord 260 is secured to the pulley66 and passes over a pulley wheel 261 supported on an arm 262 attachedto bracket 96 (see FIGURE 5). The cord then extends through the centeropening 263 in the shaft 63, through opening 263' in pin 65 and aroundpulley wheels 264 and 265 (see FIGURE 8) which are supported by bracketsconnected to upright frame member 267 attached to frame tube 108. Thecord 260 then connects with the end 266a of a movable linkage arm 266 ofa follow-up linkage (see FIGURE 7). The cord 260 terminates in a rigideyelet 270 which receives a pin 271 projecting upwardly from end 266ethrough a slot 272 in a bracket 273 which is secured to support 274 bybolts 275 (see FIGURES and 7). The support 274 is secured to uprightframe members 276 and 277 so that the bracket 273 is rigid with thevehicle frame, The arm 266 contains a center slot 280 which receives apin 281 having an upper cap 282 which is wider than the slot. The pin281 extends from a surface 283 of a post 284 so that the arm 266 issupported by the post 284 while it is permitted to 4move relative to thepost. The other end 266b of arm 266 is connected by pin 285 to one endof a link arm 286 (see FIGURE 5). End 266b is also connected to coilspring 287 anchored to a pin 288 which is secured to the vehicle frameby a bracket 289. Thus, the spring 287 moves the arm 266 in onedirection and the cable 260 pulls the arm in the other direction. It isapparent that movement of the cable 260 by the follow-up pulley 66 willpivot the linkage arm 266 about the pin 281 and cause positive movementof the link 286.

The other end of link 286 is pinned to the follow-up arm 288 which isconnected to follow-up member 259 and sleeve 1'74 of the valve 256 (seeFIGURES 5 and 6). After movement of the spool 200 of valve 256 by thegyro gimbal, the resulting movement of the wheel 55 will move thefollow-up sleeve 174 until the wheel 55 assumes a position which willcenter the valve and result in termination of the movement of the wheel.Thus, the

wheel 55 will move as a function of the displacement of gimbal 115.

A second follow-up mechanism comprises a continuous cord 290 which isconnected to link arm 286 through the member 288 at point 291 (seeFIGURE 3). The cable 290 passes around a plurality of pulleys 292 whichare supported by brackets attached to the vehicle frame and the cablewraps around the follow-up pulley 175 of the valve 170. Thus, the wheel55 is also connected through pulley 175 to the follow-up sleeve 174 ofthe valve 170 and the valve will be centered when the front wheelreaches a position corresponding to the position of the steering wheel.When the steering wheel is released, the spring 178 will move the valvespool 200 towards its center position in casing 173 which will causevalve 170 to produce a torque on the gimbal in a direction to center thegimbal, the steered front wheel and the steering wheel. Thus, theposition of the steering wheel 34 will reect the position of the frontwheel and the gimbal.

It is desirable to adjust the follow-up linkage so that precession ofthe gimbal results in small movement of the front wheel at high vehiclespeeds and large movement of the front wheel at low vehicle speeds. Thisprevents the vehicle from executing too severe a turn at high speeds.Referring to FIGURE 7, the rod 284 is connected to a piston rod 300which in turn is connected to piston 301 located within cylinder 302, Aspring 303 biases the piston to the left in FIGURE 7 in order to biasthe pin 281 toward the left end of slot 280. The enlarged extension 380eof piston rod 300 provides a space 304 in the end of the cylinder whichis connected by passage 305 to a pump 506 driven by the enginetransmission. The passage 305 is connected to exhaust through line 295containing an orice or restriction 296, and the spring end of cylinder302 is connected to exhaust `by drain line 297. The pump is driven bythe transmission at a speed which is proportional to the speed of thevehicle so that it develops a pressure in space 304 which isapproximately proportional to the square of the vehicle speed. As thepump pressure increases as a function of vehicle speed, the piston 381will be urged to the right in FIGURE 7 .moving the pin 281 toward theother end of slot 280 and toward the position shown by the phantom linesof FIG- URE 7. In order to center valve 256, a greater movement of wheel55 will be required when the pin 281 is in its full line position ofFIGURE 7, than when the pin is in its dotted line position. In otherwords, at high vehicle speeds the valve 256 is centered by less movementof the wheel 55 than is required to null the valve at low speeds andthis prevents the vehiclefrom being placed in too severe a turn at highspeeds for a given gimbal displacement. Also, at high speeds, inevitableunwanted gimbal oscillations produce negligible displacement of thesteered front Wheel.

The operation of the gyro stabilization system and steering system forthe vehicle will be described in connection with FIGURES 20-22 in whichthe major elements are shown diagrammatically and operate the same asdescribed above. In FIGURE 20, the position of the major parts are shownduring straight travel of the vehicle while in FIGURE 2l, the majorparts are in a position assumed during a turn to the left. The gyrogimbal axis 308 is substantially perpendicular to the Aroll axis, whichis indicated as a line 309 on the supporting surface 310 between the twowheels, and the gimbal axis 308 is substantially parallel to thelongitudinal centerplane of the vehicle. The spin axis of the gyrovrotor is substantially perpendicular to the longitudinal centerplanewhen the steered front wheel is in its center position about its pivotor caster axis; that is, the position in which the vehicle tends totravel in a straight line. In this position, the displaceable axis (theaxis of the front wheel displaceable about the caster or steering axis)about which the front running wheel revolves is parallel to the fixedaxis about which the rear running wheel revolves. As indicated by 13 thearrow on the rotor, the gyro rotor is spinning in a direction oppositeto the rotation of the wheels during forward travel.

To execute the turn shown in FIGURE 2l, the steering wheel 34 is movedcounterclockw'se as viewed from the rear of the vehicle and thismovement causes the valve 170 to actuate the torquing motor 158 whichproduces a torque on gimbal 115 in a counterclockwise direction asviewed from above and thereby banks the vehicle tothe left. Thereafter,the force of gravity becomes operative upon the gyro and precesses thegimbal clockwise in the direct'on of the arrow 311. In other words, whenthe roll equilibrium of the vehicle is disturbed, the gimbal precesses,according to the Well-known laws of gyroscopic precesion, in thedirection opposite to the direction in wh'c'n the vehicle is turning.The precession of the gyro gimbal will continue and will increase theturn rate of the vehicle until the component of centrifugal forceexceeds the gravitational component acting on the vehicle about its rollaxis by an amount just sufficient to precess the gyro gimbal in space atthe same rate the veh'cle is turning. When gravity acting in thedirection of arrow 314 is exactly canceled by centrifugal force actingin the direction of arrow 315, the vehicle will be in apparent verticalas illustrated by lne 316. However, during the turn, the vehicle banksshort of apparent vertical to the position indicated by line 317 or, inother words, underbanks during the desired turn. Until the gimbal isprecessing in space at the rate of turn of the vehicle, there isrelat've movement between the gimbal and vehicle, and wheel 55 continuesto pivot about its caster axis to increase the turn rate. The follow-uplinkage will cause the steered front wheel to pivot according to gimbaldisplacement but in a direction opposite to that in which the gimbalpivots. When the roll controller 34 is released or manually returnedtoward its center position to erect the vehicle from its left bank, thegimbal will be torqued in a direction to erect the vehicle and centerthe front wheel about its caster axis.

Conversely, in order to bank and turn the vehicle to the right, the rollcontroller 34 is moved clockwise, which energizes torquing motor 161,and torques the gimbal in a clockwise direction. This results in a rightbank, precessing the gimbal counterclockwise or opposite to thedirection of turn. This precession continues until it is stoppedrelative to the vehicle when a turn rate appropriate to the bank angleof the vehicle is attained.

In general, when the gyro vehicle is in motion it is alsoself-balancing. If side forces due to gusty winds or other disturbancesshould torque the vehicle about its roll axis and precess the gmbal, therelated displacement of the front wheel about its caster axis is alwaysin a direction to produce a moment to oppose the unwanted disturbingmoment. This opposing or restoring moment is the result of negativecaster or centrifugal force or both. When the vehicle is moving forward,any displacement of the gyro gimbal and the front wheel will be in adirection to equilibrate the roll moment causing the gyro displacement.Also, when the vehicle is stationary, a roll moment is applied accordingto gimbal and front wheel displacement because of negative caster. Itwill be apparent from FIGURE 22 in which the vehicle is showndiagrammatically that, because of negative caster, the center of gravityof the vehicle is moved to the left when the front wheel is moved to theright and to the right when the front Wheel is moved to the left. In anorientation, for instance, in which the rotor is spinning in a directionindicated by the arrow on the rotor in FIGURE 22, an unwanted `rollmoment in the direction of the arrow 318 will precess the gyro gimbal115 to the position indicated by the phantom lines. In this phantomposition, a moment due to gravity is effected about the roll axis of thevehicle in the direction of arrow 319 as a result of a shift of thecenter of gravity of the vehicle relative to the roll axis. In otherwords, because of negative caster,

whenever the front wheel is displaced in one direction, a roll momentdue to gravity is produced in the Opposite direction. Also when such avehicle is in motion, whenever its steered front wheel is moved in onedirection a roll moment due to centrifugal force results in the otherdirection. Therefore, when the vehicle is in motion, the roll moment dueto centrifugal force and the roll moment due to negative caster are inthe same direction and are augmentative. At a high speed, a smalldisplacement of the front wheel will produce a severe roll moment due tocentrifugal force. On the other hand, the small displacement of thefront wheel under such circumstances will result in an almost negligiblerolling moment due to negative caster. However the roll moment producedby entrifugal force at any substantial speed of the vehicle is adequateto maintain the vehicle in equilibrium. At very low speeds it isnecessary to displace the front wheel considerably, to produce a severerolling moment by centrifugal force. On the other hand, any substantialmovement of the steered front wheel wll provide a moment about the rollaxis adequate to maintain the vehicle in equiiibrium, and even when thevehicle is stationary, the roll moment due to caster will always beadequate to maintain the vehicle in equilibrium.

When the veh`cle is moving backwards, the front wheel trails and becomesthe trailing wheel and when this trailing wheel is turned to the right,the vehicle turns to the left and the roll moment due to centrifugalforce is to the right. That is, the roll moment due to centrifugal forceis in the direction the trailing wheel is steered. Also when the vehicleis steered by the trailing wheel, the trailing Wheel caster becomeslpositive rather than negative. Therefore when the trailing wheel issteered to the right the roll moment due to positive caster is to theright or in the direction of the centrifugal force moment. Thusregardless of whether or not the vehicle is moving and regardless of thedirection in which it may be traveling, a roll moment is produced upon adisplacement of the steered wheel, in a direction to maintain theequilibrium of the vehicle.

Thus, in a vehicle steered by its front wheel, the caster of the frontwheel should be negative, and in a vehicle steered by its rear wheel thecaster of the steered rear wheel should be positive in order to renderthe roll moments due to caster compatible with the roll moments due tocentrifugal force. Also, if a vehicle is steered by both its front andrear wheel, front wheel caster should be negative and rear wheel castershould be positive. This arrangement, in addition to rendering rollmoments due to caster compatible with roll moments due to centrifugalforce, simplifies the construction of the vehicle in that the steeringor caster axis is inboard regardless of whether or not front wheelsteering, rear wheel steering, or a combination of front and rear wheelsteering is employed. While the above described steering or castersuspension is preferred, neutral caster or even caster opposite to thatdescribed above, may be employed with little or no adverse effect on thestability of the vehicle when it is traveling at high speed, since theeffect of caster is negligible at high speed compared to the effect ofcentrifugal force at high speed. When such caster is employed, however,the driver must supply a corrective roll moment when the vehicle driftsin roll from an equilibrium position since a corrective roll moment isnot automatically applied to the vehicle at zero and near zero speed.However, the driver upon observing a tilt of his vehicle can restore thevehicle to an upright position by proper manipulation of the rollcontroller.

When the vehicle engine is off for a considerable length of time, thegyro rotor will lose speed and it is desirable y to have side skidswhich can be lowered on opposite sides of the Vehicle at any time tomaintain the vehicle upright. -Referring to FIGURES 1 and 2, side skids320 and 321 are shown in the up position and in the d'own position byphantom lines. Each of the skids are rotatably supported on thesupporting tube 48 and the skids are controlled by separtae hydraulicactuators 322 and 323 (see FIGURE 23). The valve 324 for the sidesupports can be manually operated for up or down movement.

The hydraulic system for the gyro vehicle is schematically shown inFIGURE 23. The engine 35 drives pump 29 which supplies uid to gyro motor132 and this motor exhausts through line 152 to the three position, fourway valve 324 which controls the side skids or packing gear. This valvecontrols fluid flow through lines 330 and 331 to the motors 322 and 323and exhausts to line 180 which leads to the three position, four wayvalve 256. When the Valve 324 is shifted to the right, the valvepassages are aligned to lower the skids and when shifted to the left,the passages are aligned to hold the skids in raised position. When thevalve 324 is in its center position fluid ows directly to line 180. Thesteering motor 80 is connected to the valve 256 by lines 257 and 258,and fluid exhausts from valve 256 to valve 170 through line 182. Thevalve 256 is shifted to either desired passage alignment by the gimbalactuated arm 250, in order to drive steering motor 80 clockwise orcounterclockwise. When the valve 256 is in its center position Huidflows directly to line 182'; bypassing steering motor 80.

Valve 170 is connected to the actuator motors 158 and 161 by lines 164and 165, respectively, and fluid leaking past the motor pistons drainsthrough lines 334 and 335 to the exhaust line 336 which returns to thetank 326. Also, the valve 170 is connected to the exhaust line 336through the line 182. When the valve 170 is shifted to the right (bycounterclockwise movement of steering wheel 34) the valve passages arealigned to pressurize motor 158 through line 181 and to connect motor161 to the exhaust line 336 through lines 183 and 182. When the valve isshifted to the left (by clockwise movement of steering wheel 34) thevalve passages are aligned to pressurize motor 161 through line 183 andto connect motor 158 to exhaust line 336 through lines 181 and 182. Whenthe valve 170 is in its center position, iiuid flows directly to exhaustline 182 bypassing the torquing actuators 158 and 161. A relief line 337includes relief valves 338 and 339 on opposite sides of the gyro motorto protect the system in the event of blockage of an exhaust passage. Amanually operated starting valve 340 is located in a secondary bypassline to exhaust the pump to the tank during engine starting and removethe pump load. Also, a check valve 341 can be located in a bypass line342 to permit the gyro motor to function as a pump in case of failure ofthe engine 35. The intake of pump 306 of the gain control system isconnected directly to the line 336 and fluid returns to the line 336through orifice 296.

Second embodiment In a second embodiment of the invention shown inFIGURE 24, the gyro rotor spins in the same direction that the wheelsrotate in forward motion as illustrated by arrow on the rotor. In orderfor the gyro to be precessed at the same rate of turn as the vehicle, itis necessary for the vehicle to overbank into a position such as isillustrated by line 350. In other words, the vehicle must bank beyondthe apparent vertical position 351 in order to produce a gravitycomponent which will precess the gyro gimbal at the vehicles rate ofturn.

In FIGURE 24, the vehicle is shown in a left bank. In order to producesuch a bank, a torque is produced on the gimbal 115 by the motor 161 ina clockwise direction (viewed from above) which Will-cause banking ofthe vehicle in a direction to produce a left turn. Gravity acting on theVehicle about its roll axis during the turn will cause the gimbal toprecess in a counterclockwise direction as indicated by arrow 352. Inother words, the vehicle overbanks `0r banks past apparent verticalsince the gyro rotor is spinning in the direction of the arrow on therotor. On the other hand, in the first embodiment, the vehicleunderbanks or banks short of apparent vertical during a turn since therotor spins in the opposite direction. As previously explained, thedirection of spin of the gyro rotor in FIGURE 24 is preferred for rearheavy vehicles. However, it is preferred that the vehicle be front heavywith the direction of rotor spin as shown in FIGURE 2l, so that thevehicle will underbank to reduce the maximum bank angle of the vehicle.

Third embodiment A third embodiment of the invention is illustrateddiagrammatically in FIGURE 25 wherein the steering wheel 362 drives thesector gear 358 to torque the gimbal housing rotor 139. The linkage 250is connected to the gimbal and actuates the valve 256 which in turncontrols the steering mechanism 76 to move the caster arm 56 supportingthe yfront w-heel 55 as in the other embodiments. A follow-up linkage266 is connected to the caster arm 56, as in the other embodiments, andmoves to center the follow-up sleeve of valve 256. However, the followupcord 298 of the rst embodiment is not necessary in the third embodimentsince the gyro gimbal 115 is geared to the steering wheel 362 in orderto provide means for manually torquing the gimbal. Because of the gearreduction between steering wheel 362. and gear 358, considerablemechanical advantage is provided for manually torquing the gimbal.

Fourth embodiment A fourth embodiment of 'the invention is illustratedin FIGURE 26 wherein the steering wheel 362 provides manual means fortorquing the gimbal 115 through the gear sector 350 and the gimbal isdirectly connected to the front wheel 55 by means of a first pinion gear380 directly connected to the gimbal and meshing with a sector gear 381directly connected to the caster arm 56. The gyro gimbal is torqued bythe steering wheel 362 to initially bank the vehicle and thereafter thevehicle will assume a bank angle in the direction of the turn which willbe maintained at a constant rate when the centrifugal `force momentprecesses the gyro gimbal at the same rate of turn as the vehicle.

Fifth embodiment While the preferred orientation of the gimbal axis isperpendicular to the roll axis and parallel to the longitudinal, vehiclecenter plane as shown in t-he first embodiment, it is understood thatthe stabilization system of the present invention will be operative whenthe axis of gimbal 115 is perpendicular to the roll axis and alsoperpendicular to the center plane as illustrated diagrammatically inFIGURES 27 and 2S. Since the rotor is spinning in a clockwise directionas indicated by arrow 385, the vehicle will underbank in a left turn toposition 386 and will overbank in a right turn. As illustrated in FIG-URE 28, the gimbal is precessed in a counterclockwise direction by theroll moment due to gravity as indicated by arrow 390, after a left `bankis produced by torquer 161' acting below the gimbal axis. The vehiclewill bank short of apparent vertical line 387, in a left turn since acentrifugal force moment is necessary to precess the gimbal in thedirection of the turn. However, when the vehicle executes a right turn,it will overbank since a gravity moment is necessary to precess thegimbal in the direction of turn. Should the direction the gyro rotorspins be reversed, the vehicle would overbank in a left turn andunderbank in a right turn.

The present invention is operative with the gyro assembly mounted atvarious angles between the two positions illustrated in which the gyrospin axis is either vertical or horizontal and normally at right anglesto the vehicle roll axis. Also, it is believed apparent that both thespin axis and the frame axis of the gyro assembly may be displaced fromthe illustrated normal right angle relation and the gyro still willbeoperative to stabilize 'the vehicle 17 but, of course, the spin axismust not be permitted to parallel the vehicle roll axis.

Since the precession rate of the gyro about its gimbal axis is inverselyproportional to IJthe angular momentum of the gyro rotor, the angularmomentum should be as great as practicable to increase roll resistance.

It will be understood that gimbal stops (not shown) may be provided inthe various embodiments to limit the angular movement of the gyro gimbalwhen the gimbal has moved through an angle at which it is no longereffective in opposing roll moments. The displace-ment of the gyroscopeofv the present invention is, of course, a function of the time integralof the various roll moments acting thereupon. To provide maximumgyroscopic resistance to roll moments, it is therefore preferred thatthe gyro gimbal be permitted to move through as large an angle aspracticable. Accordingly, an arrangement is preferred whereby thegimbal, in effecting a given roll moment by front wheel steering, isallowed to precess to the maximum safe angle throughout the speed rangeof the vehicle. To achieve such an arrangement, the gain control changesthe ratio of steered wheel movement to gimbal movement according to thesquare of the vehicle speed, so that vfor a given gimbal displacementthe resulting roll moment will be approximately constant throughout theentire speed range of the vehicle.

The configuration of the vehicle can be modified depending upon thedesired use of the vehicle and one or morewheels can be replaced byother support means. Any suitable type of power source can be used todrive the vehicle gyro motor and the other motor driven devices, and itis apparent that any suitable speed responsive means can be used toadjust the follow-up linkage between the front wheel and the gimbal inaccordance with vehicle speed. While the linkage means for controllingtorque on the gimbal and for steering the front wheel by the gimbal aredisclosed as hydraulic, it is obvious that these control linkages couldbe mechanical, electrical or any mechanical, hydraulic or electricalcombination. Various other modifications are contemplated by thoseskilled in the art without departing from the spirit and scope of theinvention.

What is claimed is:

1. A gyro vehicle comprising:

means forward and means rearward of the vehicle center of gravity forsupporting the vehicle for translational movement over a supportsurface;

said vehicle support means including means providing a longitudinal rollaxis about which said vehicle has angular freedom;

a gyro gimbal mounted on the vehicle for freedom of angular movementabout a gimbal axis;

a gyro rotor rotatably mounted in said gimbal for rotation about a rotoraxis, said gimbal axis and said rotor axis being positioned on saidvehicle for precession of said gimbal about said gimbal axis in responseto torque on said vehicle about said roll axis;

steering means responsive to the position of said gyro gimbal about saidgimbal axis for steering one of said vehicle support means; and

means for selectively applying a torque to said gimbal about said gimbalaxis to precess said vehicle about said roll axis.

2. A vehicle as defined in claim 1 wherein said vehicle roll axis isspaced below the center of gravity of said vehilce.

3. A vehicle as defined in claim 1 wherein said steering means comprisesmeans operatively connecting said gimbal and said one steered supportmeans for producing a rnechanical advantage of said gimbal over saidsupport means.

4. A vehicle as defined in claim 1 wherein:

said steering means comprises a steering motor responsive to gimbalposition for positioning said one steered support means; and

a source of energy operatively connected with said steering motor foroperating said motor.

5. A vehicle as defined in claim 1 wherein said steering means includesmeans for controlling Ithe lateral acceleration of said vehicle andtorque due to said lateral acceleration on said vehicle about said rollaxis.

6. A vehicle as defined in claim 1 wherein said steering means includesmeans for laterally displacing the vehicle center of gravity withrespect to lsaid roll axis to produce a gravitational torque on saidvehicle about said roll axis.

' 7. A vehicle as defined in claim 6 wherein said means for producinglateral displacement comprises caster means connecting said one steeredsupport means to said vehicle.

8. A vehicle as defined in claim 7 wherein said caster means providesnegative caster for said one steered support means.

9. A vehicle as defined in claim 1 wherein said gimbal axis issubstantially at right angles to said roll axis.

10. A vehicle as defined in claim 1 'wherein said vehicle support meanscomprises wheels locating said roll axis substantially in thelongitudinal centerplane of the vehicle, said one steered support meansbeing one of said wheels.

11. A vehicle as defined in claim 10 wherein said gimbal axis lies in aplane substantially parallel to said centerplane of said vehicle.

12. A vehicle as defined in claim 11 comprising means for spinning saidgyro rotor in a direction opposite to the direction of rotation of saidwheels during forward motion of said vehicle.

13. A vehicle as defined in claim 12 having means including a steeringmotor responsive to gimbal position for moving said one steered supportmeans in a direction opposite to the direction of said angular movementof said gimbal.

14. A vehicle as defined in claim 11 having:

means for spinning said gyro rotor in the same direction as thedirection of rotation of said wheels during forward motion of saidvehicle; and

means including a steering motor responsive to gimbal position formoving said one steered support means in the direction of said angularmovement of said gimbal.

15. A vehicle as defined in claim 10 wherein said gimbal axis issubstantially perpendicular to said centerplane of said vehicle.

16. A vehicle as defined in claim 10 having means for driving at leastone of said wheels to move said vehicle.

17. A vehicle as defined in claim 10 wherein said steering meanscomprises:

caster means for pivotally connecting said one steered wheel to saidvehicle.

18. A vehicle as defined vin claim 17 wherein said one steered wheelcomprises said forward support means of said vehicle, said caster meanscomprising a caster arm extending forwardly to negatively caster saidsteered wheel.

19. The vehicle defined in claim 1 comprising means responsive to thespeed of the vehicle for varying the steering ratio between said gimbaland said steering means.

20. A vehicle as defined in claim 1 wherein said torquing meanscomprises means connected to said gimbal for manually applying a torquethereto.

21. A vehicle as defined in claim 20 wherein said manual applying meanscomprises a steering wheel connected by a gear train to said gimbal.

22. A vehicle as defined in claim 1 wherein said one steered supportmeans comprises a wheel, said torque applying means comprising manuallyoperable means for applying torque to said gimbal and said steeringmeans comprising linkage means between said gimbal and said one steeredwheel.

23. A vehicle as defined in claim 22 wherein said manually operablemeans comprises manually controlled valve means and actuator meansresponsive to said valve means for selectively controlling the torqueapplied to said gimbal in either direction about the gimbal axis.

24. A vehicle as defined in claim 23 wherein said valve means comprises:

a manually moved valve element;

a follow-up element positioned -by said one steered wheel; and

means limiting the relative movement between said valve element and saidfollow-up element and for centering said valve element in said follow-upelement when said valve element is released.

25. A vehicle as defined in claim 22 wherein said steering meanscomprises a steering motor operatively connected to said linkage meansfor moving said one steered wheel.

26. A vehicle as defined yin claim 25 wherein said linkage meanscomprises:

valve means moved by said gimbal for actuating said steering motor; and

follow-up means comprising a follow-up member connected with saidsteered wheel and coacting with said valve means to position saidsteered wheel as a function of displacement of said gimbal.

27. A device as defined in claim 26 wherein said follow-up meanscomprises:

means for changing the ratio between the movement of said steered wheeland the movement of said follow-up member to maintain a ratio betweenthe steered wheel displacement and gimbal displacement varyingapproximately as the square of vehicle speed so that the turning radiusof the vehicle at high speed is greater than at low speed.

28. A vehicle as defined in claim 27 wherein said ratio changing meanscomprises a pivot pin in a link of said follow-up means positionedsubstantially in accordance with the square function of vehicle speed tovary the amount of movement of said follow-up member as the samefunction of speed.

29. A gyro vehicle comprising:

center-tracking, running wheels for supporting the vehicle fortranslational movement over a support surface and for roll freedom abouta longitudinal roll axis;

a gyro assembly having a gimbal mounted for rotation about a gimbal axisand a gyro rotor mounted in said gimbal for rotation about a rotor axis,said gimbal axis and said rotor axis being positioned on the vehicle forprocession of said gimbal in response to torque on said vehicle aboutsaid roll axis;

steering means responsive to the position of said gimbal about saidgimbal axis for steering one of said wheels;

power means for driving one of said wheels to propel the vehicle overthe support surface and for driving said rotor about said rotor axis;

means for selectively applying a torque to said gyro about said gimbalaxis to precess the vehicle abo-ut said roll axis; and

means responsive to the speed of said vehicle for controlling saidsteering means to vary the steering ratio -between said gimbal and saidsteered wheel as a function of the speed of said vehicle.

30. A vehicle as defined in claim 29 wherein said steering meanscomprises:

valve means controlled by said gimbal; and follow-up means connectedbetween said valve means and said one steered wheel;

said speed responsive means comprising means for varying the follow-upratio of said follow-up means according to the square of vehicle speed.

31. A vehicle as defined in claim 30 wherein said steering meanscomprises a steering motor controlled by said valve means for movingsaid steered wheel.

32. A vehicle as defined in claim 31 wherein said fol- 2Q low-up meanscomprises a follow-up member coacting with said valve means to positionsaid steered wheel as a function of displacement -of said gimbal.

33. A device as defined in claim 32 wherein said followup meanscomprises:

means for changing the ratio between the movement of said steered wheeland movement of said followup member to maintain a ratio between thesteered wheel dis-placement and gimbal displacement varyingapproximately as the square function of vehicle speed so that theturning radius of the vehicle at high speed is greater than at lowspeed.

34. A vehicle as defined in claim 33 wherein said ratio changing meanscomprises a pivot pin in a link of said follow-up means positionedsubstantially in accordance with the square function of vehicle speed tovary movement of said follow-up member.

35. A gyro stabilized vehicle movable on a supporting' surfacecomprising:

means forward and means rearward of the vehicle center of gravity forsupporting said vehicle for translational movement over a supportsurface;

said vehicle support means providing a longitudinal roll axis aboutwhich said vehicle has angular freedom;v

one of said support means being displaceable to impose zero forceagainst said vehicle about said roll axis when in its normal positionand to impose centrifugal force against said vehicle about said rollaxis when displaced from said normal position;

a gyroscope including a rotor mounted on a rotor -frame pivotallysupported on said vehicle for angular movement about its pivot axis inresponse to forces torquing said vehicle about said roll axis;

means controlled by angular movement of said rotor frame for positioningsaid one displaceable support means;

said positioning means including a steering motor performing work ineffecting said positioning;

a source of energy for conversion by said steering motor into mechanicalenergy to perform said work; and

means connected to said rotor frame for controlling said -energy todisplace said one displaceable support means in a direction to maintainequilibrium of said vehicle about said roll axis.

36. A vehicle as defined in claim 35 having means augmenting said energysource for converting kinetic energy stored in said rotor for emergencyutilization by said motor.

37. A vehicle as defined in claim 35 wherein said rotor frame axis issubstantially at right angles to said roll axis and lies in a planesubstantially parallel to the longitudinal centerplane of said vehicle.

38. A vehicle as defined in claim 37 wherein said vehicle support meanscomprises wheels, said one displaceable support means being one of saidwheels.

39. A vehicle as defined in claim 38 having means for spinning saidrotor in the opposite direction said wheels rotate during forwardmovement of said vehicle, said positioning means moving saiddisplaceable wheel in the opposite direction said rotor frame moves inresponse to a force torquing said vehicle about said roll axis.

40. A vehicle as defined in claim 38 having means for spinning saidrotor in the same direction said wheels rotate during forward movementof said vehicle, said positioning means moving said displaceable wheelin the same direction said rotor frame moves in response to a forcetorquing said vehicle about said roll axis.

41. A vehicle as defined in claim 35 wherein said one displaceablesupport means is positioned according to the displacement of said framein a changeable ratio, and means responsive to vehicle speed forchanging said ratio.

42. A vehicle as defined in claim 41 wherein said ratio changing meanschanges said ratio substantially as a function of the square of vehiclespeed.

References Cited UNITED STATES PATENTS 5/1911 Darrow 745.22

8/1917 Wilson KENNETH H. BETTS, Primary Examiner.

1. A GYRO VEHICLE COMPRISING: MEANS FORWARD AND MEANS REARWARD OF THEVEHICLE CENTER OF GRAVITY FOR SUPPORTING THE VEHICLE FOR TRANSLATIONALMOVEMENT OVER A SUPPORT SURFACE; SAID VEHICLE SUPPORT MEANS INCLUDINGMEANS PROVIDING A LONGITUDINAL ROLL AXIS ABOUT WHICH SAID VEHICLE HASANGULAR FREEDOM; A GYRO GIMBAL MOUNTED ON THE VEHICLE FOR FREEDOM OFANGULAR MOVEMENT ABOUT A GIMBAL AXIS; A GYRO ROTOR ROTATABLY MOUNTED ONSAID GIMBAL FOR ROTATION ABOUT A ROTOR AXIS, SAID GIMBAL AXIS AND SAIDROTOR AXIS BEING POSITIONED ON SAID VEHICLE FOR PRECESSION OF SAIDGIMBAL ABOUT SAID GIMBAL AXIS IN RESPONSE TO TORQUE ON SAID VEHICLEABOUT SAID ROLL AXIS; STEERING MEANS RESPONSIVE TO THE POSITION OF SAIDGYRO GIMBAL ABOUT SAID GIMBAL AXIS FOR STEERING ONE OF SAID VEHICLESUPPORT MEANS; AND MEANS FOR SELECTIVELY APPLYING A TORQUE TO SAIDGIMBAL ABOUT SAID GIMBAL AXIS TO PRECESS SAID VEHICLE ABOUT SAID ROLLAXIS.